Application Consistent Quiescing on vSphere 4.1
Windows 2008 guests that were created on vSphere 4.0 may need to be modified before the application consistent quiescing support for Windows 2008 in vSphere 4.1 can be used.
I prevously posted a two-part series on backups and VSS considerations which explored the challenges of ensuring that VM’s — and especially transactional applications — are backed up in a consistent state. vSphere 4.1 added full VSS support for Windows 2008 guests, but this is automatic only if the guest was created on a vSphere 4.1 host. If the VM was created on vSphere 4.0 and later moved to a vSphere 4.1 host (or upgraded), manual changes may be necessary before the application quiescing will work.
I first learned about this issue from a post at Bist Virtual. I did some searching and while I was unable to locate any KB article on the topic I was able to find the proceedure in two different VMware documents:
Each of these documents contains the following text on the issue and how to resolve it:
Application consistent quiescing of Windows 2008 virtual machines is only available when those virtual machines are created in vSphere 4.1. Virtual machines created in vSphere 4.0 can be updated to enable application consistent quiescing by modifying a virtual machine’s enableUUID attribute.
Enable Windows 2008 Virtual Machine Application Consistent Quiescing
1 Start the vSphere Client, and log in to a vCenter Server.
2 Select Virtual Machines and Templates and click the Virtual Machines tab.
3 Right‐click the Windows 2008 virtual machine for which you are enabling the disk UUID attribute, and select Power > Power Off. The virtual machine powers off.
4 Right‐click the virtual machine, and click Edit Settings.
5 Click the Options tab, and select the General entry in the settings column.
6 Click Configuration Parameters…
The Configuration Paramters window appears.
7 Click Add Row.
8 In the Name column, enter disk.EnableUUID.
9 In the Value column, enter TRUE.
10 Click OK and click Save.
11 Power on the virtual machine.
Application consistent quiescing is available for this virtual machine now that the UUID property has been enabled.
If you are backing up any Windows 2008 guests that were created on a 4.0 host or earlier, please consider the above steps to ensure that application consistent queiscing is properly functioning.